Laminates containing flexible thermoplastic laminae and at least one sheet of interlayer material are well known. These laminates find particular utility in applications requiring transparency and strength as for example, in safety laminates such as safety glass for automobiles or penetration resistant laminates for theft protection.
Presently such laminates are laid-up and bonded with adhesive interlayers under elevated temperature and pressure. The bonding is conducted usually at temperatures ranging from about 80.degree. C. to 205.degree. C. and preferably from about 110.degree. C. to about 140.degree. C.; and at pressures of from about 2 to about 300 p.s.i., and preferably at pressures of from about 150 to about 250 p.s.i. The bonding is conducted in autoclaves, hydraulic presses, and similar devices. Needless to say, such bonding processes require great capital investment and labor which results in added cost to the finished laminate.
U.S. Pat. No. 3,666,614 discloses glass-resin multi-ply laminates made according to the above described method. Such laminates suffer from the labor and expense of their construction as well as residual stresses from heat bonding.
U.S. Pat. No. 4,204,025, assigned to the same assignee as the present invention, discloses a glass-adhesive interlayer interface to which a primer is applied to increase adhesion. The adhesive interlayer is an polydiorganosiloxane-polycarbonate block copolymer and the primer is a polyvinylidine chloride. This laminate requires the application of heat and pressure for bonding and is subject to the same deficiencies described above.
Thus, there exists a need for safety laminates for use in such applications as safety glass and penetration resistant laminates which are easily assembled at the temperature of intended use and which exhibit the necessary levels of adhesion and stability.
Therefore it is an object of the present invention to provide a safety laminate containing layers of contact or pressure sensitive adhesive.
It is another object of the present invention to provide a safety laminate, the construction of which eliminates the need to use elevated temperatures and excessive pressure.
It is yet another object of the present invention to provide a method for bonding safety laminates which employs a contact or pressure sensitive adhesive.